At the heart of the Perseus galaxy cluster, a giant black hole sends pressure waves rippling through the hot gas around it, detected by the Chandra space telescope. Their period corresponds to a B-flat 57 octaves below middle C: millions of billions of times too low for human ears.
A large share of Earth's water molecules formed in the interstellar cloud that existed before the Sun was even born, more than 4.6 billion years ago. You are literally drinking a cosmic fossil.
By day, the Martian sky looks butterscotch because of fine dust hanging in the air. But at dusk, those same grains scatter blue light forward, creating a bluish glow around the Sun. Rovers have photographed these blue sunsets: the exact reverse of what we see on Earth.